Summary - Stack

Push and pop items and print the result in a mini task.

In this group you learned what a stack is, push, pop, peek and is_empty. All operations are O(1).

Stack follows LIFO: last in first out. It is used in undo, call stack and parenthesis matching.

Exercise Stack size

Write stack_size(stack). Return the number of elements. Print 3 with print(stack_size([10, 20, 30])).

Show example solution

def stack_size(stack):
    # Size
    return len(stack)
print(stack_size([10, 20, 30]))

Stack principle

Stack follows the ____ principle.

Show answer

Stack follows the LIFO principle.